exists and is an alternate of . Since this is regarding statistics I assume you mean lower case sigma (Ï) which, in statistics, is the symbol used for standard deviation, and Ï2 is known as the variance.
The Acceptable Quality Limit, commonly referred to as AQL, is a method widely used to measure a production order sample to find whether or not the entire product order has met the client's specifications. The customer then has the data to make an informed decision to accept or reject the lot.
A statistical method for computing practical quantitation limits (PQL) is developed. The PQL is operationally defined as the concentration at which the instrument response signal is 100/a times its standard deviation (e.g., for a 10% relative standard deviation (R.S.D.) a = 10). The response signal is defined as the ratio of analyte to internal standard peak areas.